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排序方式: 共有196条查询结果,搜索用时 15 毫秒
71.
Ling Ding Zhenbin Lyu Beatrice Louis Aura Tintaru Erik Laurini Domenico Marson Mengjie Zhang Wanxuan Shao Yifan Jiang Ahlem Bouhlel Laure Balasse Philippe Garrigue Eric Mas Suzanne Giorgio Juan Iovanna Yuanyu Huang Sabrina Pricl Benjamin Guillet Ling Peng 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(37)
Bioimaging has revolutionized medicine by providing accurate information for disease diagnosis and treatment. Nanotechnology‐based bioimaging is expected to further improve imaging sensitivity and specificity. In this context, supramolecular nanosystems based on self‐assembly of amphiphilic dendrimers for single photon emission computed tomography (SPECT) bioimaging are developed. These dendrimers bear multiple In3+ radionuclides at their terminals as SPECT reporters. By replacing the macrocyclic 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid cage with the smaller 1,4,7‐triazacyclononane‐1,4,7‐triacetic acid scaffold as the In3+ chelator, the corresponding dendrimer exhibits neutral In3+‐complex terminals in place of negatively charged In3+‐complex terminals. This negative‐to‐neutral surface charge alteration completely reverses the zeta‐potential of the nanosystems from negative to positive. As a consequence, the resulting SPECT nanoprobe generates a highly sought‐after biodistribution profile accompanied by a drastically reduced uptake in liver, leading to significantly improved tumor imaging. This finding contrasts with current literature reporting that positively charged nanoparticles have preferential accumulation in the liver. As such, this study provides new perspectives for improving the biodistribution of positively charged nanosystems for biomedical applications. 相似文献
72.
Katerine Diaz-Chito Jesús Martínez del Rincón Aura Hernández-Sabaté Marçal Rusiñol Francesc J. Ferri 《Journal of Mathematical Imaging and Vision》2018,60(4):512-524
This paper presents a supervised subspace learning method called Kernel Generalized Discriminative Common Vectors (KGDCV), as a novel extension of the known Discriminative Common Vectors method with Kernels. Our method combines the advantages of kernel methods to model complex data and solve nonlinear problems with moderate computational complexity, with the better generalization properties of generalized approaches for large dimensional data. These attractive combination makes KGDCV specially suited for feature extraction and classification in computer vision, image processing and pattern recognition applications. Two different approaches to this generalization are proposed: a first one based on the Kernel Trick and a second one based on the Nonlinear Projection Trick (NPT) for even higher efficiency. Both methodologies have been validated on four different image datasets containing faces, objects and handwritten digits and compared against well-known nonlinear state-of-the-art methods. Results show better discriminant properties than other generalized approaches both linear or kernel. In addition, the KGDCV-NPT approach presents a considerable computational gain, without compromising the accuracy of the model. 相似文献
73.
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75.
Silvia A. Wilinski Aura L. López de Ramos 《International Journal of Thermophysics》2010,31(11-12):2402-2415
Certain conditions of superficial properties can provoke spontaneous movement of liquids at corners such as liquid filaments. The understanding of this type of fluid dynamics phenomena is very important in many areas, for example, oil recovery or design of gathering systems of condensed fluids with capillary forces. In previous studies, several models were developed for formation and advancing of filaments at horizontal corners neglecting the gravity force. The objective of this investigation was to provide a mathematical tool to estimate the influence of gravity and to establish a clear approach for taking this effect into account or not. The proposed model is developed from a differential equation applied to an open corner for Poiseuille flow. It provides good agreement with experimental values with a maximum deviation of 3.3%. 相似文献
76.
Christopher Mulanda Aura Safina Musa Erick Ochieng Ogello Levy Michael Otwoma Wainaina Miriam Rodrick Kundu 《Lakes & Reservoirs: Research and Management》2011,16(4):265-272
The atmospheric concentration of methane (CH4) exerts a strong influence on the global climate. Notably, wetlands are important CH4 sources, whose emission represents an ecosystem process depending on such wetland characteristics as organic matter, temperature, pH, methanogenesis and CH4 oxidation, all of which vary on the basis of the type of wetland. Methane fluxes were investigated in a preliminary study in the region, using the chamber method in the open water and macrophyte‐infested wetlands of swampy and riverine types in Kilifi, a coastal district in Kenya, Africa. Despite a lack of significant interactions, the macrophyte‐infested areas emitted the highest quantity of methane of about 21.96 ± 0.04 mg CH4 m?2 day?1, compared with the water areas that emitted about 19.35 ± 0.05 mg CH4 m?2 day?1. The preliminary CH4 fluxes measured in this study are below the range reported from previous wetland field experiments in the tropics and temperate regions, indicating the need to conduct a series of similar experiments to produce more precise total estimates in the entire region. 相似文献
77.
Petersen K Ganz M Mysling P Nielsen M Lillemark L Crimi A Brandt SS 《IEEE transactions on medical imaging》2012,31(3):663-676
We present a fully automated framework for scoring a patient's risk of cardiovascular disease (CVD) and mortality from a standard lateral radiograph of the lumbar aorta. The framework segments abdominal aortic calcifications for computing a CVD risk score and performs a survival analysis to validate the score. Since the aorta is invisible on X-ray images, its position is reasoned from 1) the shape and location of the lumbar vertebrae and 2) the location, shape, and orientation of potential calcifications. The proposed framework follows the principle of Bayesian inference, which has several advantages in the complex task of segmenting aortic calcifications. Bayesian modeling allows us to compute CVD risk scores conditioned on the seen calcifications by formulating distributions, dependencies, and constraints on the unknown parameters. We evaluate the framework on two datasets consisting of 351 and 462 standard lumbar radiographs, respectively. Promising results indicate that the framework has potential applications in diagnosis, treatment planning, and the study of drug effects related to CVD. 相似文献
78.
A colleague recently mentioned that his son was looking for a PhD program and was considering security as a topic. The immediate reaction from the security researchers present was something to this effect: "No, don't. There are so many other, more interesting things in the world." This might sound like a group of disappointed people, but as far as I know, we all thoroughly enjoy working in the field and by no means regret it as a career choice. 相似文献
79.
In this paper we introduce a novel MAC protocol that provides Quality of Service (QoS) support for multimedia traffic in UWB-based
wireless local area networks. The proposed protocol allocates transmission opportunities to QoS and best effort traffic using
a set of scheduling and resource control algorithms. The algorithms account for the UWB characteristics such as the co-existence
of multiple simultaneous transmissions as well as the possibility of dynamically assigning the nodes' transmission rate and
power. The simulation results show that the proposed protocol can provide QoS support while optimizing resource utilization.
Yuechun Chu received her B.Sc. degree in electrical engineering from Shanghai University, China, in 1996 and M.Sc. degree in electrical
engineering from University of Science and Technology of China in 1999. She is currently pursuing the Ph.D. degree in the
department of electrical and computer engineering at the University of Massachusetts Amherst. Her research interests include
MAC protocol design for UWB-based networks, wireless multimedia applications, and architectures and protocols for wireless
networks with QoS guarantees.
Aura Ganz is currently an Associate Professor and Director of the Multimedia Networks Laboratory at the ECE Department, University
of Massachusetts at Amherst. She has experience in topics related to multimedia wireless networks, optical networks and ubiquitous
computing. The research results are validated by a combination of analytical, simulation and prototyping tools. She has published
a book “Multimedia Wireless Networks: Technologies, Standards and QoS” (Prentice Hall) and authored over one hundred and fifty
peer reviewed publications. Dr. Ganz received her BSc, MSc and Ph.D degrees in Computer Science from the Technion in Israel. 相似文献
80.
Security protocol for IEEE 802.11 wireless local area network 总被引:1,自引:0,他引:1
As Wireless Local Area Networks (WLANs) are rapidly deployed to expand the field of wireless products, the provision of authentication and privacy of the information transfer will be mandatory. These functions need to take into account the inherent limitations of the WLAN medium such as limited bandwidth, noisy wireless channel and limited computational power. Moreover, some of the IEEE 802.11 WLAN characteristics such as the use of a point coordinator and the polling based Point Coordination Function (PCF) have also to be considered in this design. In this paper, we introduce a security protocol for the IEEE 802.11 PCF that provides privacy and authentication, and is designed to reduce security overheads while taking into account the WLAN characteristics. We prove this protocol using the original and modified BAN logic. 相似文献